The present invention relates generally to remodelable medical graft products, including multilaminate medical graft products, having two or more regions providing differential properties, for example differential porosity and/or ingrowth of patient tissue. The invention also provides methods and systems for differentially drying remodelable materials that include vacuum drying a frozen, partially compressed and/or covered remodelable material.
As further background, extracellular matrix materials, including submucosa, are known medical graft materials. Submucosa from various biological structures such as small intestine, stomach, and the urinary bladder provide predominantly collagenous materials useful in a variety of surgical procedures where tissue support and/or ingrowth are desired. As one example, sheet-form submucosa material has been suggested and used as a surgical graft for tissue support, e.g. in hernia repair. Portions or all of the graft may include a multiple layer configuration to provide strength or reinforcement.
Often times, it is desirable to dry a medical graft product. Graft products may be dried for many reasons, such as to fuse graft material together, or for more effective storage of the sterile graft product. Several drying methods are known in the art, including lyophilization, air drying, and vacuum pressing. Drying by evaporation, or air drying, generally comprises drying a partially or completely hydrated remodelable material by allowing hydrant to evaporate from the material. Vacuum pressing generally comprises compressing a fully or partially hydrated remodelable material while the material is subject to a vacuum. Lyophilization generally includes drying a frozen material under a vacuum.
There remain needs for improved or alternative remodelable graft materials with beneficial material properties and tissue response, as well as methods and systems for making and using those materials. The present invention is addressed to these needs.